Manufacturing lines have generally evolved in complexity by the integration of highly sophisticated automation devices and methods. Gains in productivity continue to be realized as past reliance on human judgment and manipulation is replaced by processor-driven systems. The repeatability of such intelligent systems enables maximizing both quality and production speed. There has also been a general trend toward integrating fabrication and testing operations into the final assembly processes, replacing after-the-fact inspection with in-process quality control and record archiving as much as possible. Complex factory information systems are used to gather real time information about the products in their various stages of manufacture, all aimed at predictively preventing any occurrence of nonconforming product.
For automation lines that include rotating articles that extend or move in a linear direction along an axis of rotation (“axial direction”), such as a drive bit for fasteners (e.g. screws) or a bit for drilling, it is desirable to provide in-process quality control by way of detecting the axial position of the rotating article. For example, when the manufacturing process includes a step of driving screws into a product being manufactured, detection of the axial position of the drive bit can be used to determine and control various stages of the screw driving process, including when the drive bit makes contact with a screw head, when the screw makes contact with the target object, and the final relative position of the screw head after having been driven and secured at a predetermined torque.